Communication systems require backplane transceivers to strengthen and potentially shape the signal. The optical communication systems use communication standards that require that the signal be scrambled. The scrambling ensures an adequate number of transitions in the signal for the phase lock loops to synchronize. At the repeater the signals are descrambled before the signals are boosted and transmitted in some systems.
Parity information is placed in the frame before scrambling. Therefore, in order for the backplane transceiver to monitor the parity errors in the received frame, certain byte locations of the frame have to be descrambled.
Each signal requires a descrambler. The descrambling circuitry is complicated by the high data rates of the signals involved.
Thus there exists a need for a descrambling method that is simpler and less expensive to produce.